JPH05206178A - Semiconductor chip - Google Patents

Abstract

(57) [Summary] [Purpose] When mounting a semiconductor chip, eliminate bubbles generated in the brazing material. [Structure] The backside metallization 4 is formed after tapering is performed so that the periphery of the backside 3 of the semiconductor chip 1 becomes thin. [Effect] When mounting the semiconductor chip, bubbles are less likely to be generated in the brazing material between the metallized surface on the back surface of the semiconductor chip and the thick film plating and the mounting surface. Even if it occurs, the bubbles can be easily removed by scrubbing several times. The adhesive strength of the semiconductor chip can be secured, the heat dissipation is improved, and the reliability of the semiconductor chip is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor chip, and more particularly to backside processing of a semiconductor chip.

[0002]

2. Description of the Related Art In a conventional semiconductor chip, as shown in FIG. 3A, a back surface 3 of a semiconductor chip 1 is provided with a back surface metallization 4 such as gold. The front surface 2 and the back surface 3 are planes parallel to each other.

As shown in FIG. 4, there is a semiconductor chip 1 whose back surface 3 is plated with a back surface thick film plating 4a such as gold. Also in this case, the front surface 2 and the back surface 3 are planes parallel to each other.

[0004]

Since the conventional semiconductor chip is cut out from one flat wafer, the semiconductor chip shown in FIG.
As shown in (b), when the mounting surface 6 is mounted using the mounting brazing material 5, bubbles 7 are generated under the semiconductor chip 1. It is not easy to inspect for the presence of the bubbles 7 or remove the bubbles 7.

As shown in FIG. 4, when the back surface thick film plating 4a is formed, overgrowth of plating due to electric field concentration is inevitable in the peripheral portion of the back surface 3. Therefore, the back surface plating 4a rises in the peripheral portion of the back surface 3 of the semiconductor chip, so that bubbles are more likely to be generated.

The generation of bubbles reduces the adhesive strength of the semiconductor chip. In addition, there is a problem that the heat generated on the surface of the semiconductor chip does not easily escape to the mount surface and overheats to lower the reliability of the semiconductor chip.

[0007]

The semiconductor chip of the present invention is tapered so that the peripheral portion of the back surface is thin,
Since the metallization and the thick film plating are applied, it is designed so that the peripheral portion comes into contact with the mounting surface at a predetermined angle when mounting using a brazing material.

[0008]

EXAMPLE A first example of the present invention will be described.

As shown in FIG. 1A, the semiconductor chip 1
The back surface 3 is tapered so that the peripheral portion thereof is thin. A back surface metallization 4 is formed on top of this.

The semiconductor chip 1 is brazed to the mount surface 6 with a brazing material 5 as shown in FIG. 1 (b). At this time, since the back surface 3 of the semiconductor chip 1 is inclined, bubbles are less likely to be generated and the bubbles easily escape.

Therefore, air bubbles can be easily removed by moving (scrubbing) the semiconductor chip 1 in the horizontal direction several times while pressing the semiconductor chip 1 against the mounting surface 6 in a normal mounting process.

The taper processing of this embodiment can be formed by etching using a photoresist as a mask.

For example, in a 0.4 mm square semiconductor chip, when the brazing material has a thickness of 70 μm, it is considered appropriate that the taper angle is about 10 °.

Next, a second embodiment of the present invention will be described.

In this embodiment, as shown in FIG. 2A, the back surface 3 of the semiconductor chip 1 is not a flat surface but a curved surface having a predetermined curvature. Backside thick film plating 4a is formed on it.

Therefore, in the thick film plating 4a due to overgrowth, no swelling occurs in the peripheral portion, so that the curved surface is along the back surface 3.

FIG. 2B shows a state in which the semiconductor chip 1 is mounted. Since the back surface thick film plating 4a and the brazing material 5 are in contact with each other at a predetermined angle, it is possible to prevent bubbles of the brazing material.

[0018]

According to the present invention, the periphery of the back surface of the semiconductor chip is tapered so as to be thin. Therefore, when the semiconductor chip is mounted, bubbles are less likely to be generated in the metallized surface on the back surface of the semiconductor chip or in the brazing material between the thick film plating and the mounting surface. Even if it occurs, the bubbles can be easily removed by scrubbing several times.

The adhesive strength of the semiconductor chip can be secured, the heat dissipation is improved, and the reliability of the semiconductor chip is improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3A is a sectional view showing a conventional semiconductor chip. (B) is sectional drawing which shows the state which mounted (a).

FIG. 4 is a cross-sectional view showing a conventional semiconductor chip.

[Explanation of symbols]

 1 semiconductor chip 2 front surface 3 back surface 4 back surface metallization 4a back surface thick film plating 5 brazing material 6 mounting surface 7 air bubbles

Claims (1)

[Claims] 1. A semiconductor chip that is tapered so that the peripheral portion of the back surface is thin.